ROR Error: Uncaught (in promise): NullInjectorError: R3InjectorError

An attempt is being made to use the Angular material dialog in the Angular app. It is compiled without any errors. However, when the application is loaded in the browser, the following error is encountered in the browser console.

ROR Error: Uncaught (in promise): NullInjectorError: R3InjectorError(AppModule)[MatDialog -> MatDialog -> MatDialog]:
NullInjectorError: No provider for MatDialog!
NullInjectorError: R3InjectorError(AppModule)[MatDialog -> MatDialog -> MatDialog]:
NullInjectorError: No provider for MatDialog!

Why is This Error?

This error typically occurs when there is an issue with dependency injection in an Angular application.

Here’s a breakdown of the error message

ROR Error: This might be a typo, and the intended term could be “ERROR” which stands for an error in programming terminology.

Uncaught (in promise): Indicates that an error occurred within a Promise that was not handled.

NullInjectorError: This part of the error suggests that Angular’s dependency injection system is encountering a problem related to a null or undefined injector. The injector is responsible for managing the dependencies in an Angular application.

R3InjectorError: This points to a specific version of Angular’s injector system. The “R3” refers to the third rendering engine, which is the version used in Angular starting from version 9.

To troubleshoot and resolve this error, you may want to check your Angular application’s dependency injection setup. It could be caused by various issues such as missing dependencies, incorrect import statements, or issues with the Angular module configuration. Examining the specific context in your code where this error occurs can provide more insights into the root cause of the problem.